The present invention is related to a carrier for receiving a yarn or strand therearound, particularly in a high speed covering operation, for example generally in excess of 18,000 and as high as 26,000 revolutions per minute.
In the textile and related industries, various machines and processes are utilized in which a continuous length of yarn or strand is processed and thereafter wound around a yarn carrier for storage or preparation for further processing. Historically in such processes in which a package of yarn is produced around a yarn carrier, much emphasis has been placed on the speed at which the machines operate and proper handling of the yarn in such fashion that the yarn package produced around the carrier is created with precision.
In carrying out the yarn handling process, the carrier is placed over a driven spindle with the yarn being wound therearound by rotation of the spindle. The speed of operation of the process is thus primarily controlled by the rate of rotation of the spindle. Proper placement of the carrier on the spindle is important to achieve a precision wind. Misalignment of the carrier about the spindle will create not only an improperly wound yarn package, but oftentimes due to the high rotational speed of the spindle, excessive heat is generated between the spindle and the prior art carriers such that bushings within the carrier experience dimensional charge, particularly when the bushings are manufactured of synthetic polymeric materials. Shrinkage of the bushing for example, can cause the carrier to become jammed on the spindle requiring forceable removal of same which could lead to damage to the carrier and/or the spindle. Additionally, production time is lost and in general an adverse condition exists.
In certain of the processing operations, extremely high speeds are encountered, for example upwards of 18,000 and as high as 26,000 spindle revolutions per minute. For such high speeds, proper placement of the carrier around the spindle becomes particularly important. An improperly manufactured carrier, or a carrier manufactured from materials that will not withstand the rigors of high rotational speed, and/or misalignment may create very extreme adverse conditions. A misaligned carrier rotating at high speed can create noise levels that greatly exceed the standards established by OSHA as can the use of certain materials in the manufacture of a carrier. Furthermore, carriers which are not concentric within close tolerances and thus out of dynamic balance can create excessive vibration which of course abets the noise problem, as well as leading to potential vibration damage to the carrier and/or the processing equipment. Still further, high speed spindles often employ O-rings spaced along the length of same which better maintain a driven relationship between the spindle and an inside wall of the yarn carrier to prevent relative movement therebetween. Relative movement between the spindle assembly and the carrier could lead to an improper production of a yarn package or create excessive heat which could cause the carrier to become tightly secured around the spindle or if certain materials are employed, welded to the "O" rings. A high speed yarn covering operation where cover yarns are wrapped around an elastic core is such a processing operation.
In such processes as described above, it is also important that the yarn carrier be free of superficial defects that could snag or otherwise damage the yarn being wound therearound. Accordingly, certain of the prior art carriers have been manufactured from aluminum or other lightweight metals which may be anodized to present a smooth surface on the carrier which enables the carrier to receive yarn therearound without damaging the yarn. Bushings are received within some of these yarn carriers for direct contact with the spindle and such bushings in the prior art have been manufactured of metal or certain synthetic polymeric materials. The bushings are generally separate inserts that, following formation of same, are press fit or adhesively secured within the barrel of the yarn carrier. Metal bushings have the inherent fault of creating excessive noise levels as well as leading to greater expense for the part. Synthetic polymeric bushings utilized prior to the present invention have also been fraught with problems in several areas. For example, these prior art synthetic polymeric materials have not possessed adequate thermal or dimensional stability, such that, if the carrier is anodized for example, the polymeric material shrinks during the anodizing process due to excessive heat. Subsequent to anodizing, the shrunk bushing must then be reamed to reachieve a proper inside diameter for fit about the spindle. This reaming operation generally alters the concentricity of the carrier. Misalignment of carriers along the spindle can also create problems where due to the high temperatures produced by frictional engagement between the O-rings and the misaligned bushing, whereby the bushing can become welded to the O-ring which rigidly secures the carrier to the spindle and requires a forceful removal of same.
In general, prior art carriers known to applicant have utilized metallic bushings such as brass and synthetic polymeric bushings, such as molded, macerated phenolics and mineral filled nylon, all of which possess the disadvantageous characteristics noted above. The present invention overcomes the disadvantages of the prior art and is not believed to be taught or suggested by same.